Crystal assembly and mounting means therefor



Sept. 24, 1957 E. 1 MlNNlcH 2,807,731

CRYSTAL ASSEMBLY AND MOUNTING MEANS THEREFOR Filed Jan. 27,1954

1N V EN TOR. EDWARD L, M//V/U/(/ BY WMA/ff CRYSTAL ASSEMBLY AND MOUNTING MEANS THEREFOR Edward L. Minnich, Carlisle, Pa., assignor, by mesne assignments, to Standard Electronics Corporation, Newark, N. J., a corporation of Delaware Application January 27, .1954, Serial No. 406,555

8 Claims. (Cl. S10-9.2)

This invention relates to improvements in piezoelectric crystals and is concerned particularly with improved mounting or clamping means for supporting crystal and electrode assemblies.

An object of the invention is to provide a piezoelectric crystal device wherein a quartz crystal and its electrodes are supported in such a manner that the complete assembly may withstand mechanical shocks without adversely affecting performance either while the device is operative at the time of such shocks or during subsequent operative periods.

Another object of the invention is to provide improved mounting means for a crystal plate and electrode assembly which adords a protective support for the assembly and which is adapted to maintain the components in proper' relative position.

A more particular object of the invention is to provide a crystal device having a supported crystal plate and electrode assembly with exposed electrode end portions and resilient connector mounts secured to such exposed electrode end portions whereby to absorb shock and vibration to which the device may be subjected.

Still another specific object is to provide an improved crystal-electrode retaining clip.

Other and further objects and advantages will be apparent from the following detailed explanation taken in conjunction with the accompanying drawings wherein a preferred embodiment of the principles of the invention has been selected for exemplification.

In the drawings:

Fig. l is a side elevational view of a crystal device constructed in accordance with the present invention having the face wall of the outer casing removed to show the crystal and mounting means therefory within;

Fig. 2 is an end elevational view of the device shown in Fig. l with the end face wall of the outer casing similarly removed;

Fig. 3 is a top view of the device shown in Figs. 1 and 2 with the outer casing removed;

Fig. 4 is an exaggerated transverse sectional view of the crystal and electrode assembly as shown in Figs. l-3; and

Fig. 5 is a side elevational view of one of the electrode discs as shown in the preceding figures.

Referring more particularly to the drawings, wherein like numerals refer to like parts, the base or header upon which the other parts of the device are supported is an electrical insulator and may be formed of any suitable material such as glass, porcelain, non-conducting synthetic resinous material or the like. The surrounding edge 12 of the header 10 is preferably of formable or machinable material, tin plated Kovar metal, for example, and is so shaped that the bottom end walls of the cover or outer casing 14 can be fitted or soldered thereto. The members 10 and 14 when thus assembled accordingly form a housing for the quartz crystal and electrode assembly to be hereinafter particularly described.

Electrically conducting pins 16 and 18 serve as plugs for insertion into an appropriate socket and, as shown,

nited States Patent O Patented Sept. 24, 1957 extend into and through the insulating material of the base 10. To the inner ends of the pins 16 and 18 are secured as by fitting or soldering the upright members 20 and 22, respectively, which are connected to the electrodes and provide a supporting means for the crystal and electrode assembly. The supporting members 20 and 22 are formed of any suitable electrical conducting material, Phosphor bronze, for example, which preferably is spring tempered to provide a resilient support for the crystal electrode assembly to which they are secured. In the particular embodiment shown, the lower ends of the members 20 and 22 are bent at right angles to the body portions thereof and are apertured to receive the inwardly projecting ends of the pins 16 and 18 to which the members are secured by solder or the like. The upper ends of the upright members 20 and 22 are soldered or otherwise suitably secured to the electrodes of the crystal and disc assembly which will now be particularly dsecribed.

The piezoelectric quartz crystal plate 24 may be of any conventional character and, for practical considerations, the major surfaces thereof may be parallel and substantially flat, as shown. The invention contemplates that the quartz plate 24 be sandwiched between opposed in sulating discs 26 and 28 each preferably having concave inner faces on which are plated thin metal lms 27 and 29, respectively, in a pattern to provide electrodes and conducting strips which extend to and through opposed peripheral notches 30 and 32, respectively, and electrically connected to metallized regions 34 and 36, respectively, on the outer faces of the discs adjacent such notches. As best shown in Figs. l and 4, the upper end portions of conducting supports 20 and 22 are secured by solder or other suitable means to the metallized regions 34 and 36, respectively, to provide the sole support, if desired, for the crystal plate and electrode assembly.

The electrode supporting discs 26 and 28 may be identical except that the electrodes 27 and 29 and notches 30 and 32 are preferably diametrically opposed, as shown, and are formed preferably of a non-conducting material such as a ceramic, fused or crystalline quartz. In one particular embodiment of the invention, the inner surfaces of the discs 26 and 28 may be ground spherically concave to an extent that the curvature is in a range from 1A to 3%; diopter. The electrodes 27 and 29 may be obtained by depositing a thin film of silver or similar electrical conducting material on these concave faces, preferably in a paddle shape as shown in Fig. 5, so that the circular center region of the film serves as the electrode with each electrode opposed to a major face of the interposed crystal plate 24. The strip shape sections of the plated films are intended to serve only as electrical conductors and the assembly is preferably so arranged, as shown in Figs. l and 4, that these strips are positioned at angles of degrees with respect to the supporting members 20 and 22 and 180 degrees with respect to each other. As apparent best from Fig. 4, the strip portions of the plated films 27 and 29 terminate short of the peripheral edge of their respective electrode discs but extend through the beveled region or inner faces of the respective slots 30 and 32 and are in electrical connection with the outer face metallized portions 34 and 36, respectively, to which the conducting support members 20 and 22 leading to the plugs 16 and 18 are respectively secured. The thickness of the metal lms 27 and 29 and the concavity of the discs 26 and 28 are preferably so controlled that there is an air space or gap between them and the adjacent surface of the quartz plate 24 when the discs are assembled and it is only the outermost unplated regions of the discs 26 and 28 which come in physical contact with the major surfaces of the interposed quartz plate.

For retaining the crystal plate and electrode discs in assembly, the invention contemplates the provision of a clip indicated in its entirety at 38. As shown, the clip 38 is elongated and relatively narrow and is provided with a body portion 40 of shallow U-shape for receiving diametrically opposed edge portions of the assembled quartz and electrode discs. The inner faces of the opposed legs 42 of the clip body 3S are preferably arcuate in general conformity with the arcuate peripheral edges of the discs and opposed recesses 44 are provided in the inner faces of the legs 42 for receiving a leaf spring 46 which is inwardly curved to bear against the central body portion of the adjacent electrode disc whereby to provide a pressure retaining means for the assembly. The bow type leaf spring 46 may be formed of any suitable inaterial such as steel, Phosphor bronze or beryllium copper. It is desirable that the outer faces of the electrode discs 26 and 23 be rough ground to provide better frictional contact with the body portion 40 of the clip and with the spring 46 so as to avoid any tendency of the assembly to slip out of position. Since the electrode discs 26 and 28 provide their own insulation, the clip 33 may be formed of electrical conducting material if desired, for example, a strong, light material such as aluminum. The clip and assembly arrangement is also preferably such as to permit a slight relative movement of the electrode discs 26 and 28 about the crystal plate 24 when the supporting members 20 and 22 are flexed suihciently to absorb a degree of any shock to which the device may be subjected thereupon to tend to return to normal assembled position.

It will thus be apparent that the present invention provides for a very simple but highly durable crystal and electrode assembly which when supported in novel arrangement with the clip 38 can be handled or mounted as a single unit and also a device having a crystal plate protectively mounted so as to maintain its desired operativeness under conditions of extreme rough usage. The present invention further is not confined to the exact structure and arrangement of parts herein illustrated and described but embraces all Such modications thereof as come within the scope of the following claims.

I claim:

l. In a piezoelectric crystal device including an oscillator plate, insulator plates for opposed sides of said oscillator plate, the said insulator plates having a plane outer face and a concave inner face, electrodes for said oscillator plate carried by said concave inner face of said insulator plates, a recess provided in the peripheral edge of said insulator plates and connectors carried by said insulator plates leading from said electrodes and extending through said recesses to the outer faces of said insulator plates.

2. In a piezoelectric crystal device including an oscillator plate, insulator plates for opposed sides of said oscillator plate, the said insulator plates having a plane outer face and a concave inner face, the said outer faces of said oscillator plates being provided with roughened frictional surfaces, electrodes for said oscillator plate carried by said concave inner face of said insulator plates, a recess provided in the peripheral edge of said insulator plates and connectors carried by said insulator plates leading from said electrodes and extending through said recesses to the outer faces of said insulator plates.

3. In a piezoelectric crystal device including an oscillator plate, insulator plates for opposed sides of said oscillator plate, the said insulator plates having a plane outer face and a concave inner face, electrodes for said oscillator plate carried by said concave inner face of said insulator plates, a recessV provided in the peripheral edge of said insulator plates, connectors carried by said insulator plates leading from said electrodes and extending through said recesses to the outer faces of said insulator plates, andtmeans engaging. an intermediate body portion of said oscillator and insulator plate assembly to retain the same together asa unit.,

4. In a piezoelectric crystal device including an oscillator plate, insulator plates for opposed sides of said oscillator plate, the said insulator plates having a plane outer face and a concave inner face, electrodes for said oscillator plate carried by said concave inner face of said insulator plates, a recess provided in the peripheral edge of said insulator plates, connectors carried by said insulator plates leading from said electrodes and extending through said recesses to the outer faces of said insulator plates, and means loosely engaging an intermediate body portion of said oscillator and insulator plate assembly to retain the same together as a unit but to permit slight relative movement of said oscillator and insulator plates.

5. In a piezoelectric crystal device including an oscillator plate, insulator plates for opposed sides of said oscillator plate, the said insulator plates having a plane outer face and concave inner face, electrodes for said oscillator plate carried by said concave inner face of said insulator plates, a recess provided in the peripheral edge of said insulator plates, connectors carried by said insulator plates leading from said electrodes and extending through said recesses to the outer faces of said insulator plates, a clip for receiving an intermediate body portion of said oscillator and insulator plate assembly, the said clip including spring means to retain said assembly in said clip.

6. In a piezoelectric crystal device including an oscillator plate, insulator plates for opposed sides of said oscillator plate, the said insulator plates having a plane outer face and concave inner face, electrodes for said oscillator plate carried by said concave inner face of said insulator plates, a recess provided in the peripheral edge of said insulator plates, connectors carried by said insulator plates leading from said electrodes and extending through said recesses to the outer faces of said insulator plates, means engaging an intermediate body portion of said oscillator and insulator plate assembly with the peripheral recesses of said insulator plates at opposed sides of said engaging means and conductor supports secured to said electrodes connectors adjacent said recesses, the said conductor supports being resilient whereby flexibly to support said oscillator and insulator plate assembly.

7. In a piezoelectric crystal device including an oscillator plate, insulator plates for opposed sides of said oscillator plate, the said insulator plates having a plane outer face and a concave inner face, electrodes for said oscillator plate carried by said concave inner face of said insulator plates, a recess provided in the peripheral edge of said insulator plates, connectors carried by said insulator plates leading from said electrodes and extending through said recesses toA the outer faces of said insulator plates, a clip for receiving an intermediate body portion of said oscillator and insulator plate assembly with said peripheral recesses disposed at opposite sides of said clip, the said clip including spring means to retain said assembly in said clip, and resilient conductor supports for flexibly supporting said oscillator and insulator plate assembly secured to said electrode connectors adjacent said recesses.

8. In a piezoelectric crystal device including an oscillator plate, insulator plates for opposed sides of said oscillator plate, the said insulator plates having a plane outer tace and a concave inner face, electrodes for said oscillator plate carried by said concave inner face of said insulatorV plates, a recess provided in the peripheral edgc of said' insulator plates, connectors carried by said insulator plates leading from said electrodes and extending through said recesses to the outer faces of said insulator plates, a clip for receiving an intermediate body portion of said oscillator and insulator plate assembly with said peripheral recesses disposed at opposite sides of said clip, the said clip including spring means to retain said assembly in said clip, resilient conductor supports for ilexibly supporting said oscillator and insulator plate assembly secured tosaid electrode connectors adjacent said recesses, a casing including a base for housing said oscillator and insulator plate assembly and resilient conductor supports, connector plugs carried by said base and projecting inwardly of said casing and apertured bottom portions for said resilient conductor supports for engaging the projecting ends of said connectors plugs whereby electrically to secure said resilient conductor supports upon said connector plugs.

2,047,387 Scott July 14, 1936 6 Gent Mar. 4, Hight Feb. 29, Wolfskill Sept. 13, Franklin May 9, Birt May 19, Leighton June 16, Warner Oct. 20,

OTHER REFERENCES Engineering Report E-1080, Signal Corps, Engineering Labs., frontispiece and page 5. Copy in 310-9.2. 

